The present invention relates to photosentitive device and manufacturing method for the same.
Amorphous silicon photosensitive semiconductor films have been deposited on the printing drums of electrostatic photocopying machines by means of plasma CVD techniques, which utilize high frequency or direct current electric energies. The photosensitive films have to be formed to thickness as large as 5 microns. There are however several shortcomings associated with such a thick semiconductor film. Namely, cracks occur in the film; the surface is not smooth; and the film catches flakes of the product which come off from the internal surface of the reaction chamber of CVD. Because of this, though amorphous silicon semiconductors are believed to be suitable for forming photosensitive films of photocopying machines, the commercialization thereof has been deferred.
On the other hand, photosensitive organic resin films can be formed to a sufficient thickness without causing the above mentioned shortcomings. This method is desirable since printing drums can be produced only by coating the resin thereon. Particularly, mass-production is possible on a low-cost basis in accordance with this method. The life time of the printing drums, however, is relatively short. After 50-70 thousands times copying, the quality of copies becomes degraded.